A carbody of a railcar is supported by a bogie through a carbody suspension including a bolster spring. The bolster spring is a spring provided between a bogie frame of the bogie and the carbody. The bolster spring relaxes an impact transferred from the bogie to the carbody to improve ride quality of the railcar. Typically used as the bolster spring is an air spring.
The railcar is provided with pipes and wires extending between the carbody and the bogie. One of the pipes extending between the carbody and the bogie is a brake pipe. The brake pipe is a pipe connecting a compressor provided at the carbody with brake equipment provided at each of wheels of the bogie. Compressed air is supplied from the compressor through the brake pipe to the brake equipment. Examples of the wires extending between the carbody and the bogie include lead wires of electric motors, ground wires, and sensor wires. Examples of a method of wiring the lead wires of the electric motor include a method in which the lead wires are wired upward from the electric motor provided at the bogie directly to the carbody and a method in which the lead wires are gathered at a middle portion of the bogie and then wired upward to the carbody.
When separating the carbody and the bogie from each other for maintenance, the pipes and wires extending between the carbody and the bogie need to be detached to the carbody side and the bogie side. Since work of separating the carbody and the bogie from each other and coupling the carbody and the bogie to each other includes work of disconnecting and connecting the wires and pipes extending between the carbody and the bogie, such work requires a lot of labor and is complicated. A technology of simplifying the work of separating the carbody and the bogie from each other and coupling the carbody and the bogie to each other has been proposed. For example, according to the railcar described in PTL 1, an interposed member is provided between the air spring and the carbody. A brake connection pipe connected to a brake mechanism through a hose is provided in the interposed member, the brake mechanism being provided at the bogie. The brake connection pipe communicates with a positioning pin provided on an upper surface of the interposed member. Further, a connection pipe and a level controlling valve are provided in the interposed member, and compressed air is supplied through the connection pipe and the level controlling valve to an air chamber of the air spring. The connection pipe communicates with a positioning pin provided on the upper surface of the interposed member. When the carbody is placed on the interposed member, an air pressure source provided at the carbody and the brake mechanism are connected to each other through the brake connection pipe and the hose, and the air pressure source provided at the carbody and the air chamber of the air spring are connected to each other through the connection pipe.